- All Superinterfaces:
Method SummaryModifier and TypeMethodDescriptionCauses any parent nodes to get created using
CreateMode.CONTAINERif they haven't already been.Causes any parent nodes to get created if they haven't already beenHat-tip to https://github.com/sbridges for pointing this out
Methods inherited from interface org.apache.curator.framework.api.Backgroundable
inBackground, inBackground, inBackground, inBackground, inBackground, inBackground
creatingParentsIfNeededCauses any parent nodes to get created if they haven't already been
creatingParentContainersIfNeededCauses any parent nodes to get created using
CreateMode.CONTAINERif they haven't already been. IMPORTANT NOTE: container creation is a new feature in recent versions of ZooKeeper. If the ZooKeeper version you're using does not support containers, the parent nodes are created as ordinary PERSISTENT nodes.
Hat-tip to https://github.com/sbridges for pointing this out
It turns out there is an edge case that exists when creating sequential-ephemeral nodes. The creation can succeed on the server, but the server can crash before the created node name is returned to the client. However, the ZK session is still valid so the ephemeral node is not deleted. Thus, there is no way for the client to determine what node was created for them.
Even without sequential-ephemeral, however, the create can succeed on the sever but the client (for various reasons) will not know it.
Putting the create builder into protection mode works around this. The name of the node that is created is prefixed with a GUID. If node creation fails the normal retry mechanism will occur. On the retry, the parent path is first searched for a node that has the GUID in it. If that node is found, it is assumed to be the lost node that was successfully created on the first try and is returned to the caller.